1. Field of the Industrial Application
This invention relates to the locking mechanism of a connector assembly through which electrical wires, for instance, in an automobile are connected.
2. Description of the Prior Art
FIG. 7 (A) is a longitudinal sectional view showing a conventional connector housing locking mechanism, and FIG. 7 (B) is a perspective view of a locking spring employed in the locking mechanism.
As shown in FIGS. 7 (A) and (B), the locking spring d has a locking hole a at the middle, and both end portions are bent in the opposite directions, thus providing a pair of bent portions b and c. That is, the locking spring is substantially S-shaped in section. The bend portion c is fitted in a locking groove f formed in the outer side wall of a male housing g. An engaging protrusion h is extended inwardly from the outer edge of the side wall of a female connector housing g. The engaging protrusion h and the locking hole a of the locking spring d form engaging means (cf. Japanese Unexamined Utility Model Application No. 184677/1987).
The conventional connector housing locking mechanism is designed as described above. Therefore, when the male connector housing e is inserted into the female housing g, the locking spring d of the male connector housing is pushed downwardly sliding on the slope h' of the above-described engaging protrusion h, and finally when the male connector housing e has been fully inserted into the female connector housing g, the locking hole a of the locking spring d, being moved upwardly by the elastic force of the locking spring d, is engaged with the engaging protrusion h. Thus, the male connector housing e has been fixedly engaged with the female connector housing g.
The male connector housing e can be disengaged from the female connector housing g as follows: While the bent portion b of the locking spring d is being pushed downwardly to disengage the engaging protrusion h from the locking hole a, the male connector housing e is pulled out of the female connector housing g.
That is, in the conventional connector housing locking mechanism, the locking spring made of metal is employed as a component to provide a great housing locking force. That is, the conventional connector housing locking mechanism is advantageous in that it has such a great housing locking force; however, this means that it needs a great force to disengage the male connector housing from the female connector housing (by depressing the bent portion b of the locking spring d).
In general, in engagement of a male connector and a female connector, the relationships between the terminal engaging force and the connector engaging stroke are as indicated in FIG. 8 (A), in which the Y-axis represents housing locking forces, while the X-axis represents connector engaging strokes. As is apparent from the graphical representation, the housing locking force p reaches its peak with a connector engaging stroke x.sub.1, and the terminal engaging force q reaches its peak with a connector engaging stroke x.sub.2.
Therefore, an inertial locking force r, which is formed by combining the housing locking force p and the terminal engaging force q, first reaches a large peak with the connector engaging stroke x.sub.1, and next a small peak with the connector engaging stroke x.sub.2 as shown in FIG. 8 (B), in which the X'-axis represents connector strokes, and the Y'-axis represent housing locking forces.
As is apparent from the graphical representation of FIG. 8 (B), the inertial locking force must be greater than the terminal engaging force. As the number of terminals in the connector is increased, this tendency is strengthened, so that the connector engaging force is increased accordingly, and at the same time, the connector disengaging force is also increased. Thus, it gets increasingly difficult to perform a connector engaging or disengaging operation.